338
FXUS62 KCHS 060542
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1242 AM EST Sat Dec 6 2025

.SYNOPSIS...
A frontal system will maintain unsettled weather through early
next week, then cold high pressure will build in. A reinforcing
cold front will move through late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Through sunrise: The forecast area will remain within the moist
feed of southwest flow in the mid-levels while a trough axis
shifts into the mid MS Valley. In the upper-levels as the trough
axis shifts eastward a pronounced jet streak will strengthen to
150 kt across the TN Valley. At the surface, a cold front
stretches from the northeast Gulf, across north FL, and into the
western Atlantic just off the Southeast coast. This setup will
likely support the ongoing areas of stratiform rain either
holding at the current coverage or even diminishing a bit.
Overall forcing does not increase substantially so the rainfall
intensity should remain quite light, only supporting additional
amounts of a tenth of an inch or less. Lower visibilities will
likely occur with pockets of drizzle and light rain, not from
actual fog formation. Temperatures aren`t expected to fall much
through the rest of the night, with lows only getting down into
the mid to upper 40s.

Today: Aloft, the shortwave trough will quickly track eastward
across the Appalachians and toward the Mid Atlantic, while the
upper jet spreads across the same region. This will bring an
expanding area of right entrance region jet divergence across
the Southeast, coincident with precipitable water values in the
1.25-1.50" range. At the surface, the front will remain situated
to the south and southeast, keeping the forecast area solidly
on the cold side of the front. The increasing forcing from the
trough and jet aloft is expected to lead to an expansion of
stratiform rain across the forecast area, starting around late
morning or midday and continuing through the late afternoon
though the axis of precipitation should gradually shift to the
south. Additional rainfall amounts should mostly fall into the
0.25-0.50" range, with some potential for locally higher amounts
perhaps as high as 0.75" primarily along and south of a line
roughly from around Reidsville to Springfield to Beaufort. This
area where potentially higher amounts could occur is primarily
due to the rainfall lasting longer there as the axis of deepest
moisture shifts to the south. Another day of thick cloud cover
and persistent rainfall will result in temperatures struggling
to reach the low 50s for much of the area.

Tonight: The trough aloft will continue to dampen and quickly
eject out over the Atlantic and the forecast area will remain
under the influence of southwest flow. There is good model
agreement that the axis of deeper moisture will steadily shift
southward and additional rainfall will mostly be limited to
areas along and south of I-16 and along the GA coast through
midnight. Most of the forecast area should be dry after midnight
and additional overnight rain totals of a 0.10-0.25" should
only occur south of Savannah across the GA coast. Lows will be a
bit colder, with upper 30 occurring across the far inland tier,
ranging to the mid to upper 40s along the coast.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
A series of shortwaves will move through Sunday into Monday
while a front remains stalled along the Southeast coast. Ample
moisture will exist to support occasional light to moderate rain
showers. On Sunday the best coverage and greatest rain totals
will be across southeast GA and coastal southeast SC. In our far
southern areas the total rainfall Sunday through Sunday night
could exceed 0.75" while most other areas see no more than 0.2".
The strongest of the shortwaves will move through Monday
morning, bringing scattered showers to the entire area. Average
rainfall totals will be around a tenth of an inch on Monday with
the precipitation tapering off by early afternoon. Cool and dry
high pressure will build in Monday night into Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Dry high pressure will prevail through Thursday, then a
reinforcing cold front will sweep through Friday.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
The 06z TAF period begins with widespread IFR conditions which
are expected to persist through the entire forecast period. The
coverage of rainfall has diminished a bit, but we will continue
to see patches of showers or drizzle pass through the terminals
through sunrise. When rain moves through, visibilities will
lower but ceilings should remain the controlling element for
flight categories. Steady rainfall is expected to expand back
into the area by late morning and then persist into the evening
hours. This will bring ceiling heights and visibilities down for
through the afternoon hours. Rainfall will come to an end from
north to south during the evening hours, but IFR ceilings will
remain. There are indications in model guidance that dense fog
could be an issue Saturday night, but the best chances will
likely be beyond the end of the 06z TAF period.

Extended Aviation Outlook: A relatively prolonged period of
MVFR with occasional IFR ceilings expected through Monday.
Periods of rain showers could occasionally reduce visibilities
as well. Improving conditions later Monday or Monday night.

&&

.MARINE...
Today through tonight: A front will remain positioned south and
southeast of the local waters which will support modest
northwest flow through most of the period. Wind speeds aren`t
expected to be any higher than 10-15 knots, and will likely drop
off to 5-10 knots overnight while turning out of the north and
northeast. Seas should average 2-3 feet. Rounds of light
rainfall and drizzle, as well as very low clouds could produce
some visibility issues at times, but no true fog development is
expected.

A brief period of Small Craft Advisory winds is possible Monday
night as cold high pressure builds in.

&&

.TIDES/COASTAL FLOODING...
Upcoming high tide (~8:30 am): We are about 90 minutes away
from low tide and the current tidal departure at Charleston is
around 0.3 ft. The upcoming astronomical high tide is 6.7 ft
MLLW meaning we will need a 0.3 ft departure to hit the minor
coastal flood threshold of 7 ft MLLW. Given that winds aren`t
particularly supportive, we suspect we will be very close to 7
ft MLLW. We will wait a few more hours to see how departures
continue to trend before making a final decision on needing a
Coastal Flood Advisory for Charleston and coastal Colleton
counties. No coastal flooding is expected further south along
the coast based on the Fort Pulaski tide level.

Astronomical tides will remain elevated through Sunday but will
be on a declining trend. Coastal Flood Advisories could be
needed for the Sunday morning high tide cycle, but the current
forecast is for Charleston to fall just shy of the minor coastal
flood threshold.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$

NEAR TERM...BSH
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...BSH/JRL
MARINE...BSH/JRL